Samsom, Melvin

Postprandial symptoms of bloating, distension, early satiety, and nausea are associated with impaired postprandial gastric accommodation, which is detectable by means of an intragastric, barostatically controlled balloon in the proximal stomach and by ultrasound in the distal stomach. Our aim was to develop a noninvasive method to measure the entire gastric accommodation reflex. In 10 healthy volunteers, we used single photon emission computed tomography (SPECT) to measure fasting and postprandial gastric volumes. This method involved intravenous injection of99mTc pertechnetate and gastric reconstruction of tomographic images with Analyze software. SPECT-Analyze imaging detects the postprandial gastric accommodation reflex in vivo. Mean fasting gastric volume was 182 ± 11 (SE) ml and mean postprandial volume was 690 ± 32 ml ( P < 0.001). Both proximal and distal segments of stomach showed a two- to almost fourfold difference in volumes postprandially. Intraobserver coefficients of variation in estimated fasting and postprandial volumes were 9 and 8%; interobserver variations were 13 and 12%, respectively. SPECT-Analyze noninvasively measures postprandial gastric (total, proximal, and distal) accommodation in humans. This method appears promising to compare the accommodation response in health and disease and to perform mechanistic studies of the accommodation response.

The amylin analog pramlintide delays gastric emptying in type I diabetics. The effects of multiple doses of pramlintide and the mechanism of action in non-amylin-deficient humans are unknown. We investigated the effects of pramlintide on gastrointestinal and colonic transit and on the plasma pancreatic polypeptide response to the meal in a parallel-group dose-response study with subjects randomized to placebo, or 30 or 60 μg (tid, sc) of pramlintide. Pramlintide delayed gastric emptying [half-time ( t½): 112 min (SE 8.7 min), 169 min (SE 12 min), or 177 min (SE 25 min) after placebo or 30- or 60-μg pramlintide treatment, respectively; P = 0.033]. Pramlintide did not significantly affect small bowel or colonic transit. Pancreatic polypeptide concentrations in the first postprandial hour were lower with pramlintide than with placebo ( P < 0.01 for drug effect). An inverse correlation was observed between mean pancreatic polypeptide concentrations in the first postprandial hour and gastric emptying t½[Spearman correlation coefficient ( Rs) = 0.48; P = 0.044]. Pramlintide at 30 and 60 μg delays gastric emptying in healthy humans without affecting small bowel or colonic transit. Vagal inhibition is a potential mechanism of the effects of pramlintide on gastric emptying.